conf: Accept addresses enclosed by square brackets in port forwarding specifiers

Even though we don't use : as delimiter for the port, making square
brackets unneeded, RFC 3986, section 3.2.2, mandates them for IPv6
literals. We want IPv6 addresses there, but some users might still
specify them out of habit.

Same for IPv4 addresses: RFC 3986 doesn't specify square brackets for
IPv4 literals, but I had reports of users actually trying to use them
(they're accepted by many tools).

Allow square brackets for both IPv4 and IPv6 addresses, correct or
not, they're harmless anyway.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 17 insertions, 7 deletions

diff --git a/conf.c b/conf.c
index 3cf9ed8..46fcd91 100644
--- a/conf.c
+++ b/conf.c
@@ -209,14 +209,24 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
 
 		}
 
-		if (ifname == buf + 1)		/* Interface without address */
+		if (ifname == buf + 1) {	/* Interface without address */
 			addr = NULL;
-		else if (inet_pton(AF_INET, buf, addr))
-			af = AF_INET;
-		else if (inet_pton(AF_INET6, buf, addr))
-			af = AF_INET6;
-		else
-			goto bad;
+		} else {
+			p = buf;
+
+			/* Allow square brackets for IPv4 too for convenience */
+			if (*p == '[' && p[strlen(p) - 1] == ']') {
+				p[strlen(p) - 1] = '\0';
+				p++;
+			}
+
+			if (inet_pton(AF_INET, p, addr))
+				af = AF_INET;
+			else if (inet_pton(AF_INET6, p, addr))
+				af = AF_INET6;
+			else
+				goto bad;
+		}
 	} else {
 		spec = buf;